[Elecraft] Checking U1 for communication with the K3

[Cady, Fred]

Hi Art,
Try this:

The error message ERR IO3 often means that the RS232 serial interface
chip on the KIO3 board has failed. This may be caused by a static
discharge or nearby lightning strike. The chip that fails is U1 on the
KIO board, as shown in  Figure 7 25. Here is a procedure to check U1.
1.	Remove any SERIAL and ACC cables.
2.	Remove the K3's top cover.
3.	Check to see if at least -5 VDC is present on pin 8 (or the gold
through-hole just below pin 8) of U1 (-7 VDC or more is normal).
4.	Check to see if U1 is hot or visibly heat damaged.
5.	If any of these checks indicates that the magic smoke has been
let out, you will need to contact Elecraft service to determine a course
of action to fix the KIO3 board.


Fred Cady
"The Elecraft K3: Design, Configuration and Operation Second Edition"
www.ke7x.com


> -----Original Message-----
> From: elecraft-bounces at mailman.qth.net [mailto:elecraft-
> bounces at mailman.qth.net] On Behalf Of Art Nienhouse
> Sent: Monday, December 10, 2012 9:59 AM
> To: Elecraft at mailman.qth.net
> Subject: [Elecraft] Checking U1 for communication with the K3
> 
> I want to check my K3 for communication with my computer.
> 
> Does anybody know what value and which pin to check on U1 on the I O
> board lightning strike near by hit my wireless router modem and killed
> my desk top computer which was connected to my K3 rs232 port?
> I do not have at this time any computer or usb/serial adapter to test
> the radio with.
> 
> Regards
> Art
> ka9zap
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
> 
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html